Hub motor damage - advice?

It seems like I damaged the hub motor on my 1500w 48V scooter.

The rear wheel has some major resistance to turning. I can turn it by hand, but there is some “stepped” resistance, like it’s rolling over something corrogated - it stiffens up, then overcomes whatever (magnet?) for an instant before stiffening up again. When I hit the throttle, the wheel jerks and then nothing.

I live on top of a short steep hill. I usually walk it up, but last night jumped on near the top and hit the throttle. As expected, it bogged down and stopped. What have I done?

Any advice / comments appreciated.

I’d take it apart and look for damage to the armature or foreign material in the armature cavity of the motor. Electric motors run very hot and it’s not uncommon for them to throw off solder if overheated and/or overspeeded…

cracked the hub motor open, but nothing is glaringly wrong. what should i be looking for?

THANKS!!

Imgur

don’t know if these links are comin thru…

Is it hard to turn without the controller connected?

took hub out, everything looks clean. some of the coil side slats (magnets?) on the edge of the hub are a little pushed out, but no obvious damage to either rotating electric surfaces or coil wires. can i pull it apart to check wires on other side?

i’ll push slats back in, reassemble & put on power supply to test rotation. can’t turn it by hand, but power supply check will be non-controller test.

can i prep the motor magnets / surfaces w/ anything? acetone? def gonna grease all the mechanical surfaces, what about electric surfaces? humidity & water are a ■■■■■ here.

thank you guys.

http://www.flickr.com/photos/16888891@N07/2687599908/

http://www.flickr.com/photos/16888891@N07/2687599908/

[QUOTE=indysolar;4048]took hub out, everything looks clean. some of the coil side slats (magnets?) on the edge of the hub are a little pushed out, but no obvious damage to either rotating electric surfaces or coil wires. can i pull it apart to check wires on other side?

i’ll push slats back in, reassemble & put on power supply to test rotation. can’t turn it by hand, but power supply check will be non-controller test.

can i prep the motor magnets / surfaces w/ anything? acetone? def gonna grease all the mechanical surfaces, what about electric surfaces? humidity & water are a ■■■■■ here.

thank you guys.

http://www.flickr.com/photos/16888891@N07/2687599908/

http://www.flickr.com/photos/16888891@N07/2687599908/[/QUOTE]

Don’t worry so much about laminations being out of place. You could do more damage trying to push them back in should you pinch one of the windings with it. Powering up the motor on a dc supply won’t do anything but hold it from turning.
You haven’t answered, can you turn the motor without the controller connected?

You can clean the motor with electronic parts cleaner. Try not to spray the bearings directly. I know there is a high temp clear coat used for car engines. Try an auto part store. A light coat of that should be ok.

like i wrote before, i can’t spin it by hand.

there is no controller attached, the wheel assembly has been removed from the bike.

should it spin easily by hand?

With the motor off the drive assemby (bear motor) , does the wheel still have the same saw tooth resistance ? My first impression was a gear problem from a shock under load. If you still feel it with the motor off (in the wheels) then look for gear / chain damage. If not, perhapps a bearing is binding. Feel the motor when out - if you feel it there, check the motor bearings - otherwise if you feel in on the schooter and it has no gear / chain drive, check its bearings.

[QUOTE=indysolar;4057]like i wrote before, i can’t spin it by hand.

there is no controller attached, the wheel assembly has been removed from the bike.

should it spin easily by hand?[/QUOTE]

Sorry I wasn’t sure if the controller was connected. If it’s hard to turn by hand then it’s a shorted winding or a bad bearing. Do you know how to measure low resistance using a battery, bulb, and volt meter? A motor’s resistance is usually to low to get any form of accurate reading with a standard ohm meter. Use a volt meter as shown in the attached schematc. See if all the windings read the same. Should read a few 100 mv but they should all read the same within 1%. Use a large bulb like a headlight bulb (55w). The far right dots are the test probes.

[QUOTE=lazzer408;4080]Sorry I wasn’t sure if the controller was connected. If it’s hard to turn by hand then it’s a shorted winding or a bad bearing. Do you know how to measure low resistance using a battery, bulb, and volt meter? A motor’s resistance is usually to low to get any form of accurate reading with a standard ohm meter. Use a volt meter as shown in the attached schematc. See if all the windings read the same. Should read a few 100 mv but they should all read the same within 1%. Use a large bulb like a headlight bulb (55w). The far right dots are the test probes.[/QUOTE]

Thanks for the advice. I took the “hub” assembly (axle, bearings, windings) out of the “rim” assembly (magnets, rim, tire).

The hub assembly (in picture) spins freely - i can hold the axle/windings and spin the cover & bearings. I guess it’s not the bearings.

When I drop the hub into the rim (but don’t bolt the covers on), i can’t get anything to spin. Shorted windings? I’ll do the test you describe, thanks for your help!

http://www.flickr.com/photos/16888891@N07/2694813175/

Hi,

Check the main powercable where it enters the hollow axel, it might be a shortcut at that point.

        /A

The wire eh? Maybe, I’ll check it tonight.

I reconnected the motor wires to the controller, etc and applied the power while holding the axle with vise-grips.

Same thing, it would lurch forward then stop and the controller would whine.

After a few attempts, it DID turn, but only for a second or two, I was unable to get it to turn again - sounds like it might be the wire.

Good idea, I appreciate your help. This thing has been in pieces too long!!

hi …

the following are the reasosn for a tight motor

-shorted motor windings

  • if controller is connected , one leg of semi-conductor switches burnt out.
  • bearing worn out

if the hub is hard to turn with no electric attached it is a mechanical problem. ie bent shaft bad bearing something rubbing or what. if it turns hard with electric attached it cvould be wires controller magnet coils or stuff. it is usually the last thing you check :wink:

The wheel gets jammed when there are any of the following conditions

  1. Motor windings shorted
  2. Controller MOSFETs has short circuit failure… where one total leg of the controller is shorted which is leading to the windings short. Check the motor resistance by disconnecting the controller. If motor is free …then its the controller’s problem.

hope this helped.

regards
murali

do you fix this problem? because I have the same problem.

1 Like

Did you get yours fixed? Mine is doing the same!